Sargassum: A Brown Jewel or the Brown Invader?
Updated: Aug 20, 2019
Welcoming the Sargassum:
In 2011, two species of the brown, salt water macroalgae scientifically referred to as Sargassum natans and Sargassum fluitans floated their way into the Caribbean Sea and have returned almost annually since. The Sargassum seaweed is one which is never attached to the sea floor but floats on the surface of the water due to special floating berries. It is not to be confused with the sea moss used in the popular drink - if it was, then we would have definitely struck Bajan Gold!
Each year, the Caribbean islands as well as the West African coast have been experiencing influxes of the seaweed. It is believed that the new source region (which is not the Sargasso Sea) is encircled by currents running clockwise from South America to Africa and back again. During certain parts of the year, it appears as though that loop breaks down and sweeps sargassum up the Brazilian coast toward the Caribbean, blooming and growing as it moves. Recent research has indicated that the massive algal blooms occur in the equatorial area of the Atlantic known as the North Equatorial Recirculation Region (NERR). It is thought that a combination of factors such as nutrient inputs from the Amazon River and Congo River, changes in ocean chemistry and currents, increased sea surface temperatures and increased iron deposition from airborne Saharan dust could be causing the increase in growth.
Sargassum: Threat or Goldmine?
Sargassum has shown to be beneficial in small amounts but has posed massive challenges in large amounts. While floating at sea, pelagic sargassum seaweed plays an important ecological role by providing shelter and food for small species of fish and young marine species such as turtles. Many small, invertebrate animals and even other algae are associated to sargassum, which may be a potential transport vector for exotic species. There has been an increase in landings of dolphinfish (but mostly juveniles) and some coastal pelagic fishes. However, fish landings have mostly declined, while coral reefs and associated ecosystems, and sea turtle nesting beaches are degraded by the decaying seaweed or clean-up operations. If a small amount washes up on the beaches, it can be beneficial to the wildlife such as seabirds acting as an additional source of food and can also contribute to beach nourishment.
However, after one’s first experience with sargassum, many would consider it to be a nuisance. This is mainly due to the unpleasant sight and smell. Locals and visitors have been used to the white, sandy beaches and crystal clear seas and now have to adjust to the ‘Brown Invader’. In recent years, islands reported a drop in tourist arrivals during the periods of influx with some vacation cancellations while some property values diminished and investment prospects due to the smell and appearance of the beach were lower. This put a huge strain on the regional tourism industry which is the single largest sector in terms of contribution to GDP and employment in the Caribbean.
The sargassum seaweed has also impacted the fishing industry by damaging fishing gear and equipment, blocked water intakes and tangling up in nets and lines as well as making it difficult for some boats to go out fishing.
There may also be potential negative human impacts associated with the sargassum. Recent studies conducted in Mexico have discovered that the Sargassum seaweed has high levels of known toxins such as heavy metals and arsenic which could have implications when used as compost.
How Can We Use It?
So now that it seems here to stay, how can we use this resource? Some entrepreneurs and innovators have started to do research and development and have created products out of the sargassum. For example in Barbados, some of these products include being used as a growing substrate for beet root (Design Council) and other crops; as a biostimulant (Red Diamond Compost) and even in soaps (Oasis Laboratory).
What More Can Be Done?
There is still a need for greater investment from both private and public sector to assist research in order to determine the economic potential of sargassum as well as potential negative human impacts. With increased investments into innovation, we can turn this problem into profit.
Within the region, the Centre for Resource Management and Environmental Studies (CERMES) at the University of the West Indies, Cave Hill has been leading the way when it comes to sargassum research. From hosting regional sargassum workshops to more recently, the application of drone technology being used to determine the quantity of sargassum on the beach on the East Coast of Barbados, CERMES will continue to play a key role in conducting research surrounding this challenge.
The Sargassum seaweed is a natural phenomenon and so ideally, nature should be left to run its course. However, the masses of seaweed which accumulate can potentially affect human, environmental and economic health. In extreme cases, seaweed can be cleared off the beaches provided it is done in a sustainable way. Heavy machinery and equipment can lead to beach erosion and disrupt habitat. Therefore, manually cleaning up of seaweed is preferred but it is imperative to check for wildlife before. In addition, it is important to recognise that seaweed will also trap litter. The plastic materials which become trapped have a high chance of washing into the ocean and affecting the ecosystems. As a precaution, be mindful of what you leave on the beaches and pick up any garbage regardless of who it belongs to.
For best practices on management and clean up see here.
How Can You Help?
It is important to spread as much awareness as possible about how to sustainably deal with the sargassum so that collectively we can protect our environment and country. Monthly bulletins are posted by the University of South Florida Optical Oceanography Lab. The latest bulletin posted in July predicts large amounts of sargassum in the Caribbean Sea and Gulf of Mexico.
As Barbados continues to build out its roadmap for the Blue Economy, where does sargassum fit into the Blue vision? As the sargassum becomes the apparent new norm, there is a need for greater investment into research and innovation while strengthening the marine science-policy interface to better help manage the sargassum and create a national management plan. My hope is that Barbados and the Caribbean region can have a voice on the international stage and advocate that polluting countries help to pay for the clean up or that fertilizer producing companies change their ingredients. With the presence of a Ministry of Maritime Affairs and the Blue Economy and initiatives such as the UNDP Blue Lab, I am hopeful that there is great potential to encourage and support innovation and assist lead users in the space to create the next functional alternative to a plastic bag out of sargassum or maybe biofuel that can power our fishing vessels or the next local beer? Maybe sargassum is a Brown Jewel indeed!
Written by Georgina Archer, Sustainable Caribbean intern and 2019 Barbados Government Exhibition Winner and Nikola Simpson with input from Shelly-Ann Cox and Hazel Oxenford.